| 摘要 |
PURPOSE:To orientate stock by a method wherein the stock is plug-flowed by compressive force in a die or between rolls at the temperature higher than the glass transition temperature of the stock under the condition that resin sheets, the frictional force of which against the stock is larger than that between the stocks each other, are respectively pinched between the stocks made of polytetrafluoroethylene (PTFE) or of its copolymer. CONSTITUTION:PTFE stock is preheated up to 150 deg.C or higher and preferably to 200 - 327 deg.C. The temperature of a die or of rolls is selected within the range from the temperature at the surface layer part of the stock minus 100 deg.C to 400 deg.C. In order to plug-flow the stock by compressive force or the like, lubricant such as silicone oil or the like is applied onto the inner surface of the die or onto the surface of the stock. As the resin sheet, which develops large frictional force, a sheet made of PTFE blended with 5wt% or more, especially 10wt% or more of glass fibers or the like is preferable. If forming is done under the condition that three plies of the stock 5 are laminated to each other, slippage occurs between respective stocks and the stocks 6 in forming process shift each other positionally. When the stocks 5 are compressed so as to be orientated and formed under the condition that the resin sheets 7, which develop large frictional force, are placed between the stocks 5, no positional shifting of the stocks 8 occurs during forming process. The resin sheet 7 must be stretched together with the stock 8 as shown by one represented by the numeral 9. |
